SAN LEANDRO — Fire investigators think a tool cleaner was the origin of a huge fire that destroyed a family-owned machine shop and sent two employees to the hospital Friday, an Alameda County Fire Department spokeswoman said Monday.

“The fire ignited in the tool cleaner, but the investigator was not able to determine if the cause was electrical, smoking or static,” spokeswoman Aisha Knowles said.

Firefighters responded to a call at 9:35 a.m. after receiving reports of a fire at MAR’s Engineering Co. Inc., said Knowles. The fire was contained at about 10:30 a.m., but the flames destroyed the 8,000-square-foot main warehouse area at 699 Montague Ave.

Flames and heavy black smoke from the blaze could be seen from miles around.

Knowles said the attached office was salvaged but received light smoke and water damage.

Two employees were transported to San Leandro Hospital for minor injuries, including a man who suffered an asthma attack and another who sustained minor burns. There were no reported firefighter injuries, said Knowles.

Fire investigators have not determined a monetary estimate of damage, Knowles said.

The machine shop was founded in 1964 by Manuel Ambrosio Sr., and has been at the present location since 1968, according to Ambrosio’s pastor, David Kiteley of Shiloh Christian Fellowship in Oakland.

Kiteley was on a plane flying into Oakland International Airport when he saw the billowing column of smoke, and by the time he entered the airport he had received a cell phone text message telling him about the blaze.

Kiteley said Ambrosio’s son, Manuel Ambrosio Jr., now runs the shop. The business makes screws, fasteners and other industrial products.

The elder Ambrosio was in tears as he watched firefighters work. A friend, Gene Dayton, who owns a neighboring door company, said, “That’s pretty traumatic — it’s his life in there. It’s a loss for all of us.”

The company’s MAR’s name is an acronym that stands for Manny and Reine’s Engineering Co., according to a 2000 obituary for Reine Ambrosio, the late wife of Manuel Ambrosio Sr.